1. Field of the Invention
The present invention relates to aircraft cockpit flight deck data display systems and, more particularly, to methods and apparatus for assuring accurate, high integrity rendering of graphically-imaged flight data in an aircraft cockpit display system.
2. Description of the Related Art
U.S. Pat. No. 6,693,558 (“the '558 Patent), the disclosure of which is expressly incorporated by reference herein, describes an aircraft flat panel display system that includes a graphics rendering computer or processor for rendering of anti-aliased graphical imaging data derived from aircraft sensors for full-field imaging on an aircraft cockpit display screen. A comparator processor independently generates, from the same sensor data, a selected subset or “points of light” of the display screen image and compares the “points of light” data to the video data generated by the rendering processor for the same display screen pixel locations. The minimized processing requirements and simplified design of the comparator processor enable ready FAA certification of the comparator processor to meet the FAA's highest, so-called “Level A”, certification requirements. The extreme complexity and processing operations required of the rendering processor, on the other hand, make FAA “Level A” certification thereof unusually time consuming and expensive, which seriously inhibits or renders impractical the ability to update or enhance the rendering processor to take advantage of the continuing evolution and advancements in graphics processors and other hardware and software and related technologies if “Level A” certification of the rendering processor is to be maintained. To overcome this disadvantage, the “Level A” certified comparator processor checks a meaningful subset of the video data that is generated by the rendering processor for each display refresh scan to verify the integrity of the display screen image generated by the rendering processor. The rendering processor can therefore be certified to a lower certification level at which periodic changes to the hardware and/or software of the rendering processor to incorporate enhanced technology and/or functionalities, and any required FAA recertification, can be timely accomplished in a practical manner. Thus, the provision and use of the comparator processor, as disclosed in the '558 Patent, obviates the need for the otherwise-required highest level of rendering processor certification that is impractical or unavailable for accommodating technology-driven rendering processor enhancements and facilitates the use of advancements in graphics rendering hardware and software and the like to upgrade and improve the screen-generating abilities and functionality of the rendering processor.
The flat panel display system of the '558 Patent thus advantageously provides a system that can be periodically updated, without impractical certification requirements that would otherwise render the timely updating of an aircraft display system uneconomic or effectively impossible, to incorporate improved graphics processors and other technology advances that enhance and extend its ability to place on an aircraft cockpit display screen critical and other valuable information utilized by pilots in safely operating the aircraft. New aircraft can be outfitted with this system, and existing aircraft can be retrofitted to incorporate the system to replace the cockpit components and/or displays with which they were initially constructed or with which they have thereafter been fitted.
In the '558 Patent, selection of the “points of lights” to be checked by the comparator processor against the corresponding display points generated by the rendering processor is effected by choosing data points located at positions throughout the display field at which data for important aircraft and environmental and situational parameters and indications are being imaged at each periodic refresh of the display. Where for example the display includes a graphically simulated flight instrument—such by way of illustration as a graphical depiction of a conventional mechanical altimeter—one or more “points of light” can be defined at predetermined locations, such as along a graphically-imaged pointer which dynamically changes position with changes of altitude, or at changing locations, from one screen refresh to the next, on or along the imaged pointer. This procedure for selecting the “points of light” necessarily requires advance knowledge of the locations on the screen at which the data for important aircraft and environmental and situational parameters and indications are being imaged—i.e. knowledge of the manner and format in which the display screen images are being presented. See also U.S. Pat. No. 6,791,476 and No. 7,012,553, and copending U.S. patent application Ser. No. 11/054,010 filed Feb. 28, 2005, the disclosures of which are also expressly incorporated by reference herein.
Because selection of the “points of light” is based on advance knowledge of the screen display format in which the aircraft data is presented, display systems constructed in accordance with this technology must closely integrate both the controller for rendering the anti-aliased graphical image to be presented on the display and the check or comparator processor for generating the “points of light”. If a user or customer requests modifications in the format or manner of presentation of the aircraft data on the display, both the rendering controller and the comparator processor must be reprogrammed or otherwise modified so that the “points of light” continue to be selected from meaningful locations in the display field. Similarly, the systems and methods of the '558 Patent cannot easily be employed in conjunction with rendering controllers manufactured or designed by third party manufacturers or end users who are understandably reluctant to expose their often proprietary display rendering software and hardware—at least some detailed knowledge of which would be needed to code or configure the comparator processor for generating the “points of light”—to another who is a likely or potential competitor.